Ronald Koeman is set to spend heavily this summer.

Everton enjoyed a rather positive campaign under Ronald Koeman, who guided the Merseysiders to Europa League football in his first season in charge, but if they are to build on the solid foundations that the Dutchman has laid over the last few months, a strong, productive transfer window is a must.

Owner Farhad Moshiri is prepared to give Koeman and director of football Steve Walsh the funds to spend heavily this summer, and the pair are working hard to get deals over the line before the Blues start their season in late July. Major arrivals and key departures are expected, with Koeman stressing the need to increase to offensive productivity at Goodison Park.

What they need

The Blues needs to strengthen a host of positions if they harbour serious aspirations of a Champions League spot. Joel Robles and Maarten Stekelenburg have both failed to convince between the sticks while there is lack of depth in the full-back areas.

Koeman is also keen to strengthen his central defensive options and is eyeing to beefing up his attack, with the goalscoring burden currently, and almost exclusively, on the shoulders of Romelu Lukaku.

Pickford is set to swap Wearside for Merseyside.Getty Images

Who could join

Everton are closing in on a £30m deal for Sunderland goalkeeper Jordan Pickford and are also in talks with Ajax captain Davy Klaassen and Malaga forward Sandro, who is due to make a decision on a potential move before the end of the week.

Burnley's Michael Keane and Swansea City's midfield maestro Gylfi Sigurdsson have also been heavily linked with moves to Merseyside, with Koeman well aware of the need to deepen his squad due to his side's upcoming Europa League commitments.

Lukaku and Barkley are both being courted by a host of clubs.Getty Images

Who could leave

Much of the talk, as ever, surrounds Romelu Lukaku. The Belgian hitman recently said that staying at Goodison Park is 'not an option', despite having two year left on his current contract with the Blues. He seems to have his heart set on a return to Chelsea, but Everton are still keen to keep hold of him and have slapped a £100m price tag on their prized asset.

Koeman knows he needs to add significant quality to his squad this summer.Reuters

What the manager has said

"First of all we like to keep the best players but that's difficult, we know that," Koeman said in a press conference in April. "I don't know if it's possible to keep them. we have to analyse the team and what we need. We need offensive players more who score more goals, the difference between Lukaku and the rest is too big.

"It's impossible to have 15 young players in the first team, now we have enough young players in the squad and it's difficult because it's easy to come but difficult to stay. We need more players aged 26-29 to improve. Of course we stay open for young players, but little by little, they're not ready."